<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>my css 5</title>
    <style>
        .c1, .c2 {
            /*float: left;*/
            width: 300px;
        }
        .c1 {
            background-color: gray;
            float: left;
        }
        .c2 {
            background-color: lightblue;
            float: right;
        }
    </style>
</head>
<body>
<div class="c1">Hello World</div>
<div class="c2">How Are You?</div>
</body>
</html>